The present invention relates to a novel electroconductive material, particularly being improved in a solvent-resistance and antiblocking property, and being suitable for an electroconductive material in electroconductive, photoconductive and other related copying systems.
In electrophoto-copying system, a copying sheet which is prepared by coating directly a base web, such as paper or film, with a solution of a photoconductive material, for instance, a dispersion of zinc oxide, cannot give a clear copying image because, when the photoconductive layer charged by corona discharging is exposed to light, the electric charge on the exposed area is hard to disappear quickly. In order to avoid this defect, there has been adopted a means of providing an electroconductive layer as an undercoating on the surface of a base web prior to coating the photoconductive material. As an electroconductive material, a homopolymer of styrenesulfonic acid salt has been known, and it has an available electroconductivity.
However, according to the investigations of the present inventors, it has been found out that the homopolymer of styrenesulfonic acid salt is poor in the solvent-resistance and antiblocking property. The lack of a solvent-resistance in an electroconductive layer makes difficult to form a uniform thickness of photoconductive layer, since the solvent in the solution of photoconductive material readily permeates into an electroconductive layer. In the case the antiblocking property of the electroconductive layer is poor, the electroconductive base web, i.e., the base web on which the electroconductive layer is provided adheres each other when it is stored in piles for a long period and as a result, a part of the electroconductive layer is peeled out of the base web. Thus, the lack of the solvent-resistance and antiblocking property of electroconductive layer lowers the electric properties of the electroconductive base web and as a result, a clear image cannot be obtained.